Bicycle disc brake rotor

ABSTRACT

A composite material bicycle disc brake rotor is provided for a bicycle disc brake device and is designed to be mounted to a bicycle wheel hub directly or using a hub mounting member. The rotor basically includes a rotor member and a fastening member. The rotor member has a first ring-shaped member and a pair of second ring-shaped members disposed on opposite sides of the first member. The second members include a material with higher wear resistance than the first member. At least one fixing hole is formed through the first and second members and a depression is formed around the fixing hole on the surface of one of the second members. The fastening or tightening member is mounted through the fixing hole of the rotor member to fix the rotor member to another member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2004-213148. The entire disclosure of Japanese Patent Application No.2004-213148 is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a disc brake rotor, whichselectively contacts the brake pads of a bicycle disc brake caliper.More specifically, the present invention relates to a composite materialbicycle disc brake rotor designed to be mounted to a bicycle wheel hubwithout deformation of the rotor during attachment.

2. Background Information

Bicycling is becoming an increasingly more popular form of recreation aswell as a means of transportation. Moreover, bicycling has become a verypopular competitive sport for both amateurs and professionals. Whetherthe bicycle is used for recreation, transportation or competition, thebicycle industry is constantly improving the various components of thebicycle. One component that has been extensively redesigned is thebicycle brake device. In particular, in recent years, bicycles have beenprovided with disc braking devices in order to improve brakingperformance.

Bicycle disc brake devices are provided for controlling and stopping therelative rotation of the bicycle wheels. Each disc brake devicetypically includes a metal disc brake rotor that rotates in unison withone of the wheels, and disc brake calipers with brake pads thatselectively contact the disc brake rotor and apply pressure thereto toapply a braking force. Typical disc brake devices can be fluid actuated(i.e. by fluid pressure) or cable (mechanically) actuated. In any case,the disc brake rotor includes a mounting member and a ring-shaped rotormember fixed to the mounting member. The mounting member is mountable toa hub of a bicycle wheel.

It is generally important to preserve the wear resistance of such discbrake devices to create more light-weight disc brake rotors with betterheat dissipation. Particularly in the case of bicycles, which run on theuse of human power, reducing the weight is one of the most importantissues. A known example of a conventional disc brake rotor that isrelatively light weight and has relatively good heat dissipationcapability includes a rotor member that uses composite materials formedby laminating a stainless steel sheet to both sides of a core ofaluminum or aluminum alloy. See, for example Japanese Patent 2679162.

Conventional rotor members involving the use of composite materials havea plurality of fixing holes. A flanged collar member involving the useof a zinc alloy material is mounted in the fixing holes.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved bicycledisc brake rotor. This invention addresses this need in the art as wellas other needs, which will become apparent to those skilled in the artfrom this disclosure.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a bicycle disc brakerotor for a bicycle disc brake device that uses two members of differenttypes of materials, which are tightened to a hub or a hub mountingmember.

Another object of the present invention is to provide a bicycle discbrake rotor that uses two members of different types of materialstightened to a hub or a hub mounting member, which reduces and/oreliminates compression/deformation of the different materials.

Yet another object of the present invention is to provide a bicycle discbrake rotor that uses two members of different types of materialstightened to a hub or a hub mounting member, which facilitates effectivetightening of the fasteners such as pins or bolts so that the disc brakerotor member is sufficiently attached to the hub or hub mounting member.

Yet another object of the present invention is to provide a bicycle discbrake rotor that uses two members of different types of materials, whichis relatively strong yet relatively lightweight.

Yet still another object of the present invention is to provide abicycle disc brake rotor that uses two members of different types ofmaterials, which is relatively simple and inexpensive to manufacture andassemble.

In other words, the basic objective of the present invention is toprevent problems when bicycle disc brake rotor members involving the useof two members of different types of materials are tightened to a hub ormounting member.

Rotor members constructed of composite materials such as aluminum alloyflanked by hard stainless steel alloy can be tightened by means oftightening pins, such as rivets each having a head or heads and a shaft,to the hub or a mounting member. When such a rotor member is tightenedwith a tightening pin to the hub or mounting member in this manner, therelatively softer aluminum alloy component in the middle can becomecompressed by the head(s) of the tightening pins when the parts aretightened, resulting in dents on the surface. Such dents on the surfacecan make it more difficult for the tightening pin to work effectively,with the possibility of an insufficiently tightened rotor member.

The present invention seeks to prevent such problems when bicycle discbrake rotor members involving the use of two members of different typesof materials are tightened to a hub or mounting member, such as isoutlined in the objects of the present invention.

The foregoing objects can basically be attained by providing a bicycledisc brake rotor for a bicycle disc brake device. The bicycle disc brakerotor basically includes a rotor member, at least one fastening memberand optionally a hub mounting member. The rotor member includes a firstring-shaped member and a pair of second ring-shaped members disposed onopposite sides of the first ring-shaped member. The second ring shapedmembers include a material with higher wear resistance than the firstring-shaped member. At least one fixing hole is formed through the firstring-shaped member and the second ring-shaped members with at least onedepression formed in the surface of one of the second ring-shapedmembers around the fixing hole. The at least one fastening member ismounted through the fixing hole of the rotor member. The fasteningmember is configured and arranged to fixedly attach the rotor member toanother member.

This disc brake rotor is designed to be directly fixedly attached to abicycle wheel hub or a hub mounting member that can be removably andnon-rotatably coupled to a bicycle wheel hub.

In this disc brake rotor, the rotor member is constructed of a firstring-shaped member, a second ring-shaped member disposed closely on bothsides of the first member, a fixing hole, and a depression. A fixinghole is provided in the first and second members, and a depression isformed on the surface of one of the second members. Preferably, the headof a fixing means, such as a bolt or tightening pin (i.e. crimp pin orrivet), is disposed in the depression, and the fixing means passesthrough the fixing hole to fix the rotor member to the mounting member.The second member, which is disposed on both sides of the first memberand comes into contact with the brake pad, is a material with greaterwear resistance than the first member. Here, a depression is formedaround the fixing hole, so that when the depression is formed, forexample, by compressing the first readily deformable first member bymeans of a stepped pressing process while the second member is mountedon both sides of the first member, or a component serving as apreliminary depression of the first member is formed by being cut into acylindrical shape through a machining process, for example, and one ofthe second members is aligned with it to form a concave shape by meansof a pressing process or the like, the first member will be less likelyto be further compressed, with less likelihood of becoming dented. Therotor member can thus be effectively tightened by the fixing means whenfixed to the mounting member, without any tightening problems.

The foregoing objects can also basically be attained by providing abicycle disc brake rotor for a bicycle disc brake device. The bicycledisc brake rotor basically includes a rotor member, at least onefastening member and optionally a hub mounting member. The rotor memberincludes a first ring-shaped member and a pair of second ring-shapedmembers disposed on opposite sides of the first ring-shaped member. Thefirst ring-shaped member has at least one first fixing componentextending radially inwardly from an inner peripheral surface thereof.Each of the second ring-shaped members has at least one second fixingcomponent extending radially inwardly from an inner peripheral surfacethereof aligned with the first fixing component. The second ring shapedmembers include a material with higher wear resistance than the firstring-shaped member. The at least one fastening member is configured andarranged to fixedly attach the first and second fixing components of therotor member to another member.

In this disc brake rotor, the rotor member is constructed of a firstring-shaped member, a second ring-shaped member disposed closely on bothsides of the first member, a fixing hole, and a depression. A fixinghole is preferably provided in the first and second members at the firstand second fixing components, and a depression is preferably formed onthe surface of one of the second members. The head of the fixing means,such as a bolt or tightening pin (i.e. crimp pin or rivet), ispreferably disposed in the depression so that the fixing means passesthrough the fixing hole to fix the rotor member to the mounting member.The second member, which is disposed on both sides of the first memberand comes into contact with the brake pad, is a material with greaterwear resistance than the first member. Here, a depression is preferablyformed around the fixing hole, so that when the depression is formed,for example, by compressing the first readily deformable first member bymeans of a stepped pressing process while the second member is mountedon both sides of the first member, or a component serving as apreliminary depression of the first member is formed by being cut into acylindrical shape through a machining process, for example, and one ofthe second members is aligned with it to form a concave shape by meansof a pressing process or the like, the first member will be less likelyto be further compressed, with less likelihood of becoming dented. Therotor member can thus be effectively tightened by the fixing means whenfixed to the hub, without any tightening problems.

A bicycle disc brake rotor in accordance with another aspect of thepresent invention includes a hub mounting member configured to bereleasably attached to a bicycle hub to rotate therewith, and thefastening member fixedly attaches the rotor member to the hub mountingmember.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the hub mounting member includes a hub attachmentcomponent that is configured to be releasably non-rotatably mounted tothe bicycle hub and a rotor attachment component that is disposed on anouter periphery of the hub attachment component, the rotor member beingfixedly attached to the rotor attachment component with the fasteningmember. In other words, the hub mounting member includes a hubattachment component that is disposed in the center and that is mountedon the hub; and a rotor attachment member that is disposed on the outerperiphery to attach the rotor member. In this case, the mounting memberis constructed of a hub attachment component and a rotor attachmentcomponent to make the mounting member more lightweight.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention has a hub mounting member that includes a materialwith greater thermal conductivity than the second members. In otherwords, the hub mounting member involves the use of a material withgreater thermal conductivity than the second member. In this case, heatis more readily conducted from the second member to the mounting member,affording better heat dissipation.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first ring-shaped member includes at least onefirst fixing component extending radially inwardly from an innerperipheral surface thereof, and each of the second ring-shaped membersincludes at least one second fixing component extending radiallyinwardly from an inner peripheral surface thereof that are aligned withfirst fixing component, the fixing hole extending through the firstfastening component and the second fastening components aligned with thefirst fastening component.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the depression is formed utilizing a stepped pressingprocess that presses the surface of one of the second members using amold. In other words, the depression is formed by a stepped pressingprocess for pressing the surface of one of the second members using amold. In this case, it is easier to form a depression in which therelatively soft first member is compressed by stepped pressing to becomethinner than the other components.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, a plurality of the fixing holes are disposed atspaced intervals in a circumferential direction about the rotor member.In other words, a plurality of fixing holes are disposed at intervals inthe rotating direction. In this case, the plurality of fixing holeensures that the rotor member is prevented from rotating and is fixed tothe hub or mounting member.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first member includes a material with greaterthermal conductivity than the second members. In other words, the firstmember involves the use of a material with greater thermal conductivitythan the second member. In this case, the heat produced by the frictionbetween the second member and the brake pad is more readily conductedthrough the first member to the mounting member or hub, affording betterheat dissipation. Moreover, the formation of the depression increasesthe area in contact between the first member and one of the secondmembers, thereby affording even better heat dissipation.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first member is constructed of an aluminum alloy,and the second member is constructed of stainless steel alloy. In thiscase, the wear resistance is preserved by the second member constructedof stainless steel alloy, and the first member constructed of aluminumalloy results in lighter weight and better heat dissipation.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the second member has undergone a hardening process.In this case, the hardening improves the hardness of the surface of thesecond member that is in contact with the brake pad, resulting in evenbetter wear resistance.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the rotor member is formed by pressing clad materialscomprising sheets of the hardened stainless steel which will become thesecond members pressure welded by means of hot rolling or forge weldingto both sides of the aluminum sheet that is to become the first member.In this case, the first and second members are pre-pressure welded,making it even more difficult for them to become separated. Also, thereis no need for them to be fixed individually when fixed to the mountingmember or hub, thus simplifying the fixing process.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first member is between 0.5 mm and 1.5 mm thick,and the second member is between 0.2 mm and 0.8 mm thick. In this case,the first member with lower wear resistance located in the middle isrelatively thick, at between 0.5 and 1.5 mm, allowing the overallthinness to be preserved while preserving strength. The second memberwith higher wear resistance located on both sides is relatively thin, atbetween 0.2 and 0.8 mm, allowing the overall thinness to be preservedwhile staying more lightweight.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first ring-shaped member includes a plurality offirst fixing components extending radially inwardly therefrom in acircumferentially spaced arrangement and each of the second ring-shapedmembers includes a plurality of second fixing components extendingradially inwardly therefrom in a circumferentially spaced arrangement tobe aligned with the first fixing components, and the fixing holes areformed in the first and second fixing components. In other words, thefirst and second members separately comprise first and second ringcomponents; first protrusions, in which the aforementioned fixing holeis formed, that protrude radially on the inner periphery of the firstand second ring components and that are formed at intervals in theperipheral direction; and second protrusions, wherein the aforementionedfixing hole and depression are formed in one, and the fixing hole isformed in the other. In this case, fixing holes are provided in theinwardly extending protruding protrusions, making it easier to fix thefirst and second members to the mounting member or hub.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the fastening member includes a head that is receivedin the depression and a shaft of smaller diameter than the head. Inother words, the fixing means comprises a head that is housed in thedepression and a shaft of smaller diameter than the head. In this case,the head is housed in the depression so that the depression is lesslikely to become deformed when pressed.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the head is received in the depression so as not toprotrude from the depression. In other words, the head is housed in thedepression so as not to protrude from the depression. In this case, thehead of the fixing means does not protrude from the depression, therebypreventing it from coming into contact with the other parts such as thecaliper when the disc brake rotor is rotated, while also making thebrake device more compact as a whole.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the fastening member is a tightening pin fortightening the first and second members together to another member. Inother words, the fixing means comprises a tightening pin for tighteningthe first and second members en masse to the mounting member or hub. Inthis case, the tightening pin allows both members to be firmly fixed tothe mounting member or hub with a simple structure.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the tightening pin is constructed of stainless steelalloy. In this case, the use of stainless steel alloy affords betterstrength and corrosion resistance.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the second ring-shaped members are constructed asseparate members from each other.

In a bicycle disc brake rotor in accordance with another aspect of thepresent invention, the first ring-shaped member includes a plurality ofthe first fixing components extending radially inwardly therefrom in acircumferentially spaced arrangement and each of the second membersincludes a plurality of the second fixing components extending radiallyinwardly therefrom in a circumferentially spaced arrangement to bealigned with the first fixing components.

A depression is formed around the fixing hole in the present invention,so that when the depression is formed, for example, by compressing thefirst readily deformable first member by means of a stepped pressingprocess while the second member is mounted on both sides of the firstmember, or a component serving as a preliminary depression of the firstmember is formed by being cut into a cylindrical shape through amachining process, for example, and one of the second members is alignedwith it to form a concave shape by means of a pressing process or thelike, the first member will be less likely to be further compressed,with less likelihood of becoming dented. The rotor member can thus beeffectively tightened by the fixing means when fixed to the hub ormounting member, without any tightening problems.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses a preferred embodiment of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a side elevational view of the front portion of a bicycle witha disc brake rotor for a bicycle disc brake device coupled thereto inaccordance with a preferred embodiment of the present invention;

FIG. 2 is an enlarged, partial side elevational view of the portion ofthe bicycle illustrated in FIG. 1, with the disc brake rotor for a discbrake device coupled thereto;

FIG. 3 is an exploded schematic (diagrammatic) view of the disc brakecaliper of the disc brake device illustrated in FIGS. 1 and 2;

FIG. 4 is a top plan view of the disc brake operating mechanism of thedisc brake device illustrated in FIGS. 1-3;

FIG. 5 is a schematic (diagrammatic) structural diagram of the discbrake operating mechanism illustrated in FIG. 4;

FIG. 6 is a first (outside) elevational view of the disc brake rotorfors a disc brake device illustrated in FIGS. 1 and 2;

FIG. 7 is a second opposite (inside) elevational view of the disc brakerotor illustrated in FIG. 6;

FIG. 8 is an enlarged, partial schematic cross sectional view of thedisc brake rotor illustrated in FIGS. 6-7, as seen along a radiallyextending section line passing through one of the fastening members;

FIG. 9 is a flow chart of the processes for producing the disc brakerotor illustrated in FIGS. 1, 2 and 6-8;

FIG. 10 is a side elevational view corresponding to FIG. 2 of anotherembodiment of the present invention; and

FIG. 11 is an enlarged, partial schematic (diagrammatic) cross sectionalview of a disc brake rotor illustrating the formation of the depressionin accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained withreference to the drawings. It will be apparent to those skilled in theart from this disclosure that the following descriptions of theembodiments of the present invention are provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

Referring initially to FIG. 1, a bicycle 10 is illustrated with abicycle disc brake device 12 mounted thereon in accordance with apreferred embodiment of the present invention. The various parts and/orcomponents (technology) of bicycles such as the bicycle 10 are generallywell known in the bicycle art. Accordingly, the bicycle 10 and thevarious structural and operating components of the bicycle 10 will notbe described and/or illustrated in detail herein, except as related tothe bicycle disc brake device 12 of the present invention.

The bicycle 10 is conventionally known, except for certain parts of thedisc brake device 12, as explained below. Accordingly, the bicycle 10includes a bicycle frame 14 with a handlebar 15, front and rear forks 16(only front fork shown), front and rear wheels 17 (only front wheelshown), and a conventional drive train (not shown). The drive train (notshown) basically includes front and rear sprockets, a chain, front andrear derailleurs, etc. or the like. The front fork 16 illustrated hereinhas a double crown suspension, Of course, it will be apparent to thoseskilled in the art from this disclosure that he bicycle 10 may alsoinclude various conventional parts or components as needed and/ordesired without departing from the present invention.

The bicycle disc brake device 12 basically includes a bicycle disc brakecaliper 21 mounted on the front fork 16, a bicycle disc brake rotor 22and a brake operating mechanism 23.

The disc brake caliper 21 is attached to the front fork 16 of thebicycle 10 at a location near the disc brake rotor 22, and appliestightening force to the disc brake rotor 22 to stop it from rotating. Asillustrated in FIGS. 2 and 3, the brake caliper 21 basically includes ahousing 50 and piston unit 51. The housing 50 is constructed of athermally conducting material such as an aluminum alloy. The housing 50includes a first housing member 52 a and second housing member 52 bfixedly attached (e.g. bolt-joined) to the first housing member 52 a.The two housing members 52 a and 52 b have substantially the same shape,but are substantially mirror images of each other. Hydraulic tubing 86is connected between the second housing member 52 b and the brakeoperating mechanism 23 to supply hydraulic brake fluid (e.g. mineraloil) to both housing members 52 a and 52 b.

The second housing member 52 b has an outwardly extending flange formingan attachment member 54 for fixedly attaching (bolting) the brakecaliper 21 to the front fork 16. When both housing members 52 a and 52 bare bolted tightly together (i.e. assembled), a brake slot is formedbetween them to allow the disc brake rotor 22 to be partially receivedtherein to rotate through the slot. As illustrated in FIGS. 3 and 5, tworound cylindrical recesses 57 a are formed in the first housing member52 a with two pistons 74 received therein, while two round cylindricalrecesses 57 b are formed in the second housing member 52 b with twopistons 74 received therein. In other words, the recesses 57 a and 57 bmovably support (house) the pistons 74 within the disc brake caliper 21.Additionally, fluid conduits (oil lines) 58 a and 58 b are formed in thefirst and second housing members 52 a and 52 b, respectively, in orderto supply hydraulic brake fluid (oil) to the cylindrical recesses 57 aand 57 b, respectively. The hydraulic brake fluid (oil) supplied fromthe brake operating mechanism 23 via the tubing 86 flows into the secondhousing member 52 b and through the oil lines 58 a and 58 b into therecesses 57 a and 57 b, allowing the piston unit 51 to be operated.

As illustrated in FIG. 3, the piston unit 51 basically includes the fourpistons 74 and a pair of brake pads 76. The pistons 74 slidably fit intothe pairs of cylindrical recesses 57 a and 57 b to move between releasepositions and braking positions (not shown). The brake pads 76 aredisposed at the free ends (tips) of the pistons 74 (i.e. outside of therecesses 57 a and 57 b) and move in unison. Thus, when the pistons 74are moved from the release positions to the braking positions, the brakepads 76 also move from the release positions to the braking positions.When in the braking position, the brake pads 76 squeeze (pinch) the discbrake rotor 22 and to apply a friction force in order to apply aslowing/stopping force (brake force) to the front wheel 17 by means ofthe disc brake rotor 22. When in the release position, the brake pads 76move away from (withdraw) the disc brake rotor 22, allowing the discbrake rotor 22 to freely rotate. The piston unit 51 basically movesrelative to the housing 50 in a conventional manner. In other words, thedisc brake caliper 21 is basically conventional, except as discussedand/or illustrated herein.

The disc brake rotor 22 is fixedly attached to the hub 17 a of the frontwheel 17 to rotate together with (in conjunction with) the front wheel17. As illustrated in FIG. 2, the disc brake rotor 22 basically includesa hub mounting member 22 a, a ring-shaped rotor member 22 b and aplurality of fastening or tightening members (pins) 22 c such as crimppins, rivets or bolts. The hub mounting member 22 a is located in thecenter with the ring-shaped rotor member 22 b serving as the outerperipheral frictional or engagement surface of the disc brake rotor 22.The tightening pins 22 c are used to fixedly attach (serve as the fixingmeans for fixing) the rotor member 22 b to the hub mounting member 22 a.

The hub mounting member 22 a is preferably constructed of a lightweight,rigid material such as a metallic material (e.g. an aluminum alloy). Thehub mounting member 22 a includes a hub attachment component 40 and arotor attachment component 41. The hub attachment component 40 isdisposed in the center or central area of the hub mounting member 22 aand mounted on the hub 17 a. The rotor attachment component 41 isdisposed on the outer periphery of the hub mounting member 22 a forattaching the rotor member 22 b thereto. The hub attachment component 40is a cylindrical member. A serrated element 40 a is non-rotatablymounted on the hub 17 a. The serrated element 40 a is preferablyintegrally formed on the inner periphery of the hub attachment component40 to non-rotatably mate with a similar element of the hub 17 a torotate with the front wheel 17. The rotor attachment component 41 has aplurality of (i.e. five) arm portions 41 a that extend radiallyoutwardly from the hub attachment component 40. A fixing hole 41 b isformed in the tip of each of the arm portions 41 a for fixing the rotormember 22 b to the hub attachment component. Additionally, as seen inFIGS. 6 and 8, each arm portion 41 a includes a recessed area formed inone side at the tip portion with the respective fixing hole 41 bdisposed at the recessed area.

As illustrated in FIGS. 6 through 8, the rotor member 22 b is formed ofa composite material. In particular, the rotor member includes a pair ofouter (second) members 91 and 92, each preferably constructed ofstainless steel alloy. In any case, pair of outer (second) members 91and 92 are preferably constructed of the same material, the materialhaving greater friction resistance (higher coefficient of friction) thanaluminum. The pair of outer (second) members 91 and 92 are pressurebonded to opposite axial sides (i.e. both sides) of an inner (first)member 90, which is preferably constructed of aluminum alloy. In anycase, the inner (first) member is preferably constructed of a materialwith greater thermal conductivity than the stainless steel alloy (i.e.the material of the second members 91 and 92). Moreover, the hubmounting member 22 a (preferably constructed of aluminum alloy) ispreferably constructed of a material with greater thermal conductivitythan the second members 91 and 92. The first member 90 and secondmembers 91 and 92 of the rotor member 22 b have substantially the sameshapes. The first member 90 includes a first ring component 90 a, aplurality of (five) first fixing components 90 b protruding radiallyinwardly and formed at equally spaced intervals in the peripheraldirection along the inner periphery of the first ring component 90 a,and a plurality of weight reduction (lightening) holes 90 c formed inthe first ring component 90 a to reduce the weight. Similarly, thesecond member 91 includes a second ring component 91 a, a plurality of(five) second fixing components 91 b protruding radially inwardly andformed at equally spaced intervals in the peripheral direction along theinner periphery of the second ring component 91 a, and a plurality ofweight reduction (lightening) holes 91 c formed in the second ringcomponent 91 a to reduce the weight. The second member 92 is verysimilar to the second member 91. Thus, the second member 92 includes asecond ring component 92 a, a plurality of (five) second fixingcomponents 92 b protruding radially inwardly and formed at equallyspaced intervals in the peripheral direction along the inner peripheryof the second ring component 92 a, and a plurality of weight reduction(lightening) holes 92 c formed in the second ring component 92 a toreduce the weight. The radial width of the first and second ringcomponents 90 a, 91 a, and 92 a are larger than corresponding dimensionof the brake pads 76 in contact with the second ring components 91 a and92 a. This arrangement is provided so the entire (radial) width of thesecond ring components 91 a and 92 a will not be subject to wear, and sothat any such wear will not result in differences (reduction) in thelevels (thickness) between the second fixing components 91 b and 92 b.As a result, there will be less stress concentrated in such areas withdifferences in levels, and thus, a substantial increase in brakingstrength can be achieved. In other words, the brake pads 76 and thefirst and second ring components 90 a, 91 a, and 92 a are configured andarranged such that wear is minimized or eliminated at the second fixingcomponents 91 b and 92 b, and thus, fastening strength can be maintainedand increased stress at the second fixing components 91 b and 92 b dueto wear can be minimized.

Each of the first fixing components 90 b includes a fixing hole 90 dformed therein, each of the second fixing components 91 b includes afixing hole 91 d formed therein, and each of the second fixingcomponents 92 b includes a fixing hole 92 d formed therein. The fixingholes 90 d, 91 d, and 92 d are formed at the same radial positions asthe fixing holes 41 b. In other words, the fixing holes 90 d, 91 d, and92 d are configured and arranged to be aligned with the fixing holes 41b. A cylindrical depression 91 e is formed at each of the fixing holes91 d by stepped pressing (one surface of the second member 91 is pressedusing a mold) is formed around the fixing hole 91 d in the one side ofsecond member 91.

The fastening or tightening members (pins) 22 c are preferablyconstructed of a stainless steel alloy. Each of the fastening ortightening members (pins) 22 c is mounted in one of the depressions 91 eto extend through one of the fixing holes 90 d, one of the fixing holes91 d, and one of the fixing holes 92 d. Each tightening pin 22 c has ahead 93 and a shaft 94 with a smaller diameter than the head 93. Thediameter of the head 93 is smaller than that of the depression 91 e suchthat the head 93 is received in the depression 91 e so as not toprotrude beyond the depression 91 e. In particular, in this embodiment,the end surface of the head 93 is substantially flush with the surfaceof the second member 91 in which the depression 91 e is formed. Thetightening pins 22 c fixedly attach (tighten) the rotor member 22 b tothe hub mounting member 22 a. Here, the thickness t1 of the first member90 is between 0.5 and 1.5 mm, and the thickness t2 of the second members91 and 92 is between 0.2 mm and 0.8 mm. Setting the thickness of themembers 90 and 91/92 within this range will result in a relativelythicker first member 90 that is located in the center and has lower wearresistance, thus ensuring a relatively lighter weight overall whilepreserving strength. The relatively thinner second members 91 and 92with higher wear resistance located on both sides also ensure arelatively lighter weight overall while preserving strength. In otherwords, the members 91 and 92 are preferably thinner than the member 90.

During the forming of the depressions 91 e, the relatively softer firstmember 90 is compressed by a stepped pressing process or the like usedto form the depressions 91 e, making the member 90 thinner than theother components at the locations on the depressions 91 e. The thicknessof the relatively harder second member 91, on the other hand, is notdeformed very much when the depressions 91 e are formed by the steppedpressing process or the like. Thus, when the depressions 91 e are formedby a stepped pressing process, only the softer first member 90 iscompressed and becomes thinner when pressed, whereas the thickness ofthe harder second member 91 does not become deformed. Accordingly, whenthe rotor member 22 b is tightened to the hub mounting member 22 a bythe tightening pin 22 c, the first member 90 will not become furthercompressed, and thus, dents resulting from such further compression canbasically be eliminated. As such, when the rotor member 22 b is fixed tothe hub mounting member 22 a by the tightening pins 22 c, it can beeffectively tightened by the tightening pins 22 c, without problems inbeing fixed to the hub mounting member 22 a.

This sort of rotor member 22 b is produced by pressing a clad materialcomprising hardened stainless steel sheets (which will become the secondmembers 91 and 92) press welded by means of hot rolling or forge weldingto both sides of an aluminum sheet (which will become the first member90). Specifically, as illustrated in FIG. 9, the aluminum sheet servingas the first member 90 and the stainless steel sheets serving as thesecond members 91 and 92 are first prepared (Step S1), the aluminumsheet is sandwiched between the stainless steel sheets, and thesandwiched core is then press welded by means of hot rolling or forgewelding to produce a clad material comprising a stainless steel sheetpress welded to both sides of the aluminum sheet (Step S2). Theresulting clad material is then press punched to form a rotor member 22b of the desired shape (Step S3). A stepped pressing process is thencarried out to form the depressions 91 e (Step S4). During the steppedpressing process, a plurality of cylindrical molds for forming thedepressions 91 e are prepared and are pressed by a press machiningdevice around the fixing holes 91 d. Any warping in the rotor member 22b that is ultimately obtained is then corrected to finish the rotormember 22 b (Step S5).

As illustrated in FIGS. 4 and 5, the brake operating mechanism 23operates the piston unit 51 of the disc brake caliper 21 to forciblypinch the disc brake rotor 22 between the brake pads 76, therebyapplying a braking force to the front wheel 17. The brake operatingmechanism 23 is integrally attached to the right end of the handlebar15. The brake operating mechanism 23 basically comprises a brake leverassembly 80, master cylinder 81, master piston 82, and operating fluidtank 83.

As illustrated in FIGS. 4 and 5, the brake lever assembly 80 includes abracket 84 mounted on the handlebar 15, and a lever component 85pivotally mounted between the brake and release positions on the bracket84. The bracket 84 is integrally formed with the master cylinder 81therein. The master piston 82 and operating fluid tank 83 are supportedby the bracket 84. The master piston 82 is movably (slidably) attachedinside the master cylinder 81. Specifically, the operating fluid tank 83is attached to the master cylinder 81 and communicates with a holeinside the master cylinder 81 to supply operating fluid. The masterpiston 82 is connected at one end to the lever component 85, allowingthe master piston 82 to move axially inside the master cylinder 81.Thus, when the lever component 85 is operated, the master piston 82moves axially inside the master cylinder 81. With this arrangement, themaster piston 82 moves inside the master cylinder 81, allowing pressureoil to move through the hydraulic tubing 86 connected to the brakecaliper 21. The pressure oil moves the pistons 74 and brake pads 76, sothat the disc brake rotor 22 is pinched, thus applying a braking forceto the front wheel 17.

In this disc brake device 12, when the brake operating mechanism 23 isoperated, the piston unit 51 and brake pads 76 of the brake caliper 21move between the release positions, where the disc brake rotor 22 canfreely rotate, and the braking positions (not shown), where brakingforce is applied to the disc brake rotor 22. The brake operatingmechanism 23 is basically constructed and operates in a conventionalmanner. Accordingly, the brake operating mechanism 23 will not beexplained and/or illustrated in detail herein, except as related to thepresent invention. In other words, the brake operating mechanism 23 willnot be explained and/or illustrated in detail herein, except as neededto make and use the present invention.

In this case, the depressions 91 e are formed such that the first member90 is thinner than the other components is provided around the fixinghole 91 d, so that when the depressions 91 are formed, for example, bycompressing the first readily deformable first member 90 by means of astepped pressing process while the second members 91 and 92 are mountedon both sides of the first member 90, or a component serving as apreliminary depression of the first member 90 is formed by being cutinto a cylindrical shape through a machining process, for example, andone of the second members is aligned with it to form a concave shape bymeans of a pressing process or the like, the first member 90 will beless likely to be further compressed, with less likelihood of becomingdented. The rotor member 22 b can thus be effectively tightened by thetightening pin 22 c to the hub mounting member 22 a when tightened bythe tightening pin 22 c, without any tightening problems on the hubmounting member 22 a.

OTHER EMBODIMENTS

A) In the previous embodiment, the rotor member 22 b was mounted to thehub 17 a indirectly utilizing the hub mounting member 22 a. However, asshown in FIG. 10, a modified rotor member 122 b may also be directlyfixedly attached to a modified hub 117 a without using the hub mountingmember 22 a of the previous embodiment. Such an arrangement isparticularly suited to certain wheel spoking arrangements such as thatshown in FIG. 10 for example. In this case, a rotor mounting component117 b with a plurality of (e.g. four) radially extending arms 117 c isformed on or provided on (e.g. integrally formed with) the hub 117 a.The modified rotor member 122 b has a first member 90 and second members91 and 92 in the same manner as in the above embodiment. Thus, the firstand second members 90, 91, and 92 comprise the same first and secondring components 90 a, 91 a, and 92 a as above, with first and secondfixing components 90 b, 91 b, and 92 b protruding radially inwardly andformed at equally spaced intervals in the peripheral direction along theinner periphery of the first and second ring components 90 a, 91 a, and92 a. The first and second fixing components 90 b (four), 91 b (four),and 92 b (four) are tightened by means of, for example, a plurality oftightening pins 122 c, to the tips of the arms 117 c. A plurality ofdepressions 191 e for housing the heads 193 of the tightening pins 122 care formed in one side of second fixing components 91 b by means of astepped pressing process in a manner identical to the previousembodiment. In this embodiment, the first member 90 and the secondmembers 91 and 92 are illustrated with weight reduction (lightening)holes (not numbered) in FIG. 10, which have a different configurationfrom the previous embodiment. These holes provide the same function asthe holes 90 c, 91 c and 92 c of the first embodiment. Moreover, thefirst member 90 and the second members 91 and 92 illustrated in FIG. 10have fewer fixing components 90 b (four), 91 b (four), and 92 b (four)than the previous embodiment. Thus, this embodiment is substantiallyidentical to the previous embodiment. Accordingly, some parts that arefunctionally identical to parts of the previous embodiment will be giventhe same reference numerals for the sake of convenience and brevity,even though they are not identical to the parts of the previousembodiment. In view of the similarities between this embodiment and theprevious embodiment, it will be apparent to those skilled in the artfrom this disclosure that the descriptions and illustrations of theprevious embodiment also apply to this embodiment, except as explainedand illustrated herein.

B) In the above embodiments, the first member 90 was constructed ofaluminum alloy, and the second members 91 and 92 were constructed ofstainless steel alloy. However, the present invention is not limited tothese materials. The second members 91 and 92 may be constructed of anymaterial with higher wear resistance than the first member 90. The firstmember 90 should be lighter and have better thermal conductivity thanthe second members 91 and 92, to ensure a lighter weight and better heatdissipation. The first member 90 can be constructed of a light carbonfiber-reinforced resin or carbon graphite, and the second members 91 and92 may be constructed of a ceramic. The first member 90 may also beconstructed of a titanium or magnesium alloy.

C) In the above embodiments, the examples of the fastening or tighteningmembers (fixing means) included tightening pins. However, but the fixingmeans is not limited to tightening pins. For example, the fixing meansmay include bolts.

D) In the above embodiments, the depressions 91 e and 191 e were formedby a stepped pressing process. However, as illustrated in FIG. 11, forexample, a cylindrical depression 290 e may be machined into the firstmember 290. In such an arrangement, the one side of the second member291 may have a plurality of depressions 291 e, and a plurality ofprotrusions 291 f to fit into depressions 290 e of the first member 290.The depressions 290 e may be formed by a pressing process or the like.The first and second members 290, 291, and 292 are pressure bonded toform a modified rotor member 222 b having a depression 291 e. In view ofthe similarities between this embodiment and the previous embodiments,it will be apparent to those skilled in the art from this disclosurethat the descriptions and illustrations of the previous embodiment alsoapply to this embodiment, except as explained and illustrated herein.

E) In the above embodiments, the tightening pins 22 c and 122 c wereconstructed of stainless steel alloy. However, the tightening pins 22 cand 122 c may alternatively be constructed of aluminum alloy. With suchan arrangement, heat will be conducted more efficiently through thetightening pins from the first and second members to the mounting memberor hub, for better heat dissipation.

As used herein to describe the present invention, the followingdirectional terms “forward, rearward, above, downward, vertical,horizontal, below and transverse” as well as any other similardirectional terms refer to those directions of a bicycle equipped withthe present invention. Accordingly, these terms, as utilized to describethe present invention should be interpreted relative to a bicycleequipped with the present invention.

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “member”, “component” or “element” whenused in the singular can have the dual meaning of a single part or aplurality of parts. Finally, terms of degree such as “substantially”,“about” and “approximately” as used herein mean a reasonable amount ofdeviation of the modified term such that the end result is notsignificantly changed. These terms of degree should be construed asincluding a deviation of at least ±5% of the modified term if thisdeviation would not negate the meaning of the word it modifies.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. Furthermore, the foregoing descriptions of theembodiments according to the present invention are provided forillustration only, and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

1. A bicycle disc brake rotor for a bicycle disc brake device, thebicycle disc brake rotor comprising: a rotor member including a firstring-shaped member and a pair of second ring-shaped members disposed onopposite sides of the first ring-shaped member, the second ring shapedmembers including a material with higher wear resistance than the firstring-shaped member, at least one fixing hole being formed through thefirst ring-shaped member and the second ring-shaped members with atleast one depression formed in the surface of one of the secondring-shaped members around the fixing hole; and at least one fasteningmember mounted through the fixing hole of the rotor member, thefastening member is configured and arranged to fixedly attach the rotormember to another member.
 2. The bicycle disc brake rotor according toclaim 1, further comprising a hub mounting member configured to bereleasably attached to a bicycle hub to rotate therewith, and thefastening member fixedly attaches the rotor member to the hub mountingmember.
 3. The bicycle disc brake rotor according to claim 2, whereinthe hub mounting member includes a hub attachment component that isconfigured to be releasably non-rotatably mounted to the bicycle hub anda rotor attachment component that is disposed on an outer periphery ofthe hub attachment component, the rotor member being fixedly attached tothe rotor attachment component with the fastening member.
 4. The bicycledisc brake rotor according to claim 2, wherein the hub mounting memberincludes a material with greater thermal conductivity than the secondmembers.
 5. The bicycle disc brake rotor according to claim 1, whereinthe first ring-shaped member includes at least one first fixingcomponent extending radially inwardly from an inner peripheral surfacethereof, and each of the second ring-shaped members includes at leastone second fixing component extending radially inwardly from an innerperipheral surface thereof that are aligned with first fixing component,the fixing hole extending through the first fastening component and thesecond fastening components aligned with the first fastening component.6. The bicycle disc brake rotor according to claim 1, wherein thedepression is formed utilizing a stepped pressing process that pressesthe surface of one of the second members using a mold.
 7. The bicycledisc brake rotor according to claim 1, wherein a plurality of the fixingholes are disposed at spaced intervals in a circumferential directionabout the rotor member.
 8. The bicycle disc brake rotor according toclaim 7, wherein the first ring-shaped member includes a plurality offirst fixing components extending radially inwardly therefrom in acircumferentially spaced arrangement and each of the second ring-shapedmembers includes a plurality of second fixing components extendingradially inwardly therefrom in a circumferentially spaced arrangement tobe aligned with the first fixing components, and the fixing holes areformed in the first and second fixing components.
 9. The bicycle discbrake rotor according to claim 1, wherein the first member includes amaterial with greater thermal conductivity than the second members. 10.The bicycle disc brake rotor according to claim 1, wherein the firstmember is constructed of an aluminum alloy, and the second members areconstructed of a stainless steel alloy.
 11. The bicycle disc brake rotoraccording to claim 10, wherein the second member includes a hardenedmaterial that has undergone a hardening process.
 12. The bicycle discbrake rotor according to claim 11, wherein the rotor member isconstructed by pressing clad materials including sheets of the hardenedstainless steel that are pressure welded by hot rolling or forge weldingto both sides of an aluminum sheet.
 13. The bicycle disc brake rotoraccording to claim 1, wherein the first member is between 0.5 mm and 1.5mm thick, and each of the second members is between 0.2 mm and 0.8 mmthick.
 14. The bicycle disc brake rotor according to claim 1, whereinthe fastening member includes a head that is received in the depressionand a shaft of smaller diameter than the head.
 15. The bicycle discbrake rotor according to claim 14, wherein the head is received in thedepression so as not to protrude from the depression.
 16. The bicycledisc brake rotor according to claim 14, wherein the fastening member isa tightening pin for tightening the first and second members together toanother member.
 17. The bicycle disc brake rotor according to claim 16,wherein the tightening pin is constructed of stainless steel alloy. 18.The bicycle disc brake rotor according to claim 1, wherein the secondring-shaped members are constructed as separate members from each other.19. A bicycle disc brake rotor for a bicycle disc brake device, thebicycle disc brake rotor comprising: a rotor member including a firstring-shaped member and a pair of second ring-shaped members disposed onopposite sides of the first ring-shaped member, the first ring-shapedmember having at least one first fixing component extending radiallyinwardly from an inner peripheral surface thereof and each of the secondring-shaped members having at least one second fixing componentextending radially inwardly from an inner peripheral surface thereofaligned with the first fixing component, the second ring shaped membersincluding a material with higher wear resistance than the firstring-shaped member, at least one fastening member configured andarranged to fixedly attach the first and second fixing components of therotor member to another member.
 20. The bicycle disc brake rotoraccording to claim 19, wherein the first ring-shaped member includes aplurality of the first fixing components extending radially inwardlytherefrom in a circumferentially spaced arrangement and each of thesecond members includes a plurality of the second fixing componentsextending radially inwardly therefrom in a circumferentially spacedarrangement to be aligned with the first fixing components.